Live-tracking rhizobial switch from rhizosphere to plant-confined colonization modes

实时跟踪根瘤菌从根际到植物限制定植模式的转变

• 批准号: 431352836
• 负责人: Professorin Dr. Anke Becker
• 金额: --
• 依托单位: Zentrum für Synthetische Mikrobiologie (SYNMIKRO)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/431352836?language=en
• 关键词: Live; tracking; rhizobial; switch; rhizosphere

Legumes establish beneficial nitrogen-fixing symbioses with rhizobia bacteria that supply nitrogen for the plant within specialized root organs, known as nodules. Early stages of this interaction require crucial molecular exchanges in the rhizosphere before the host plant reprograms for bacterial root entry. While most rhizobia species infect the roots of their host via a newly formed root hair intracellular apoplastic compartment called infection thread (IT), others colonize their host plants via alternative and less studied intercellular infection modes. In both cases, rhizobia must switch from a rhizospheric to an infecting state where they become confined within plant apoplastic compartments. Up to now, it has been technically challenging to study bacterial reprogramming within plant-confined environments during early infection, as these events are restricted to a few root cells. Live-Switch is an innovative project aimed at addressing the crucial but largely unexplored question of how rhizobia cope with the drastic transition from free living to infective within-host state. The project will take advantage of Medicago and Lotus model legume systems establishing intracellular or intercellular infection modes, to decipher at the single cell level how rhizobia cells reprogram during the switch from a free-living to a host-confined environment. The project will combine live cell imaging and mutant analyses of both bacteria and plant partners to dissect the dynamics of rhizobial signal production, cell proliferation and motility and the cross talk with the plant partner. The integration of data in a final mathematical model will permit a better understanding of the dynamics of spreading and proliferation of rhizobia in the in planta IT compartment. Live-Switch relies on an ideal integrated and collaborative frame between the French and German groups, that with their solid and complementary expertise in molecular and cell biology of both plant and bacteria partners, will be able to address the exciting question of how dynamic environments shape the in vivo switch of bacterial reprograming to in planta lifestyles.

豆类与根瘤菌建立了有益的固氮共生体，根瘤菌在被称为根瘤的特殊根器官中为植物提供氮素。这种相互作用的早期阶段需要在根际进行关键的分子交换，然后宿主植物重新编程以使细菌进入根。大多数根瘤菌通过一种新形成的根毛胞质外体感染寄主植物的根，而另一些根瘤菌则通过另一种较少研究的细胞间感染方式侵染寄主植物。在这两种情况下，根瘤菌必须从根际转换到感染状态，在这种状态下，它们会被限制在植物的质外体隔间内。到目前为止，在植物限制的环境中研究早期感染期间的细菌重编程一直是技术上的挑战，因为这些事件仅限于少数根细胞。Live-Switch是一个创新项目，旨在解决根瘤菌如何应对从自由生活到宿主国家内感染的急剧转变这一关键但基本上未被探索的问题。该项目将利用Medicago和Lotus模型豆科植物系统建立细胞内或细胞间感染模式，在单细胞水平上破译根瘤菌细胞如何在从自由生活环境转换到宿主受限环境的过程中重新编程。该项目将结合活细胞成像和对细菌和植物伙伴的突变分析，以剖析根瘤菌信号产生、细胞增殖和运动的动态，以及与植物伙伴的串扰。将数据整合到最终的数学模型中，将使人们能够更好地了解根瘤菌在植物IT隔间中传播和繁殖的动力学。Live-Switch依赖于法国和德国集团之间的理想集成和协作框架，凭借他们在植物和细菌合作伙伴的分子和细胞生物学方面坚实和互补的专业知识，将能够解决令人兴奋的问题，即动态环境如何塑造体内细菌重新编程到植物生活方式的切换。